Laura Erickson's For the Birds

Summer Weather’s effects on birds

This summer’s extreme heat has had some effects on our north woods bird life. In many areas the heat combined with lack of rain for weeks at a time sent earthworms deep underground, farther than robins can reach. In response, many robins closed up shop early, as far as nesting goes, and have already joined fall feeding flocks. Flocks of migrating robins have been spotted in many northern areas now. They won’t head south very soon—that would put them in even hotter, drier conditions. But they are gathering in fruiting trees and shrubs, feeding on their high-energy autumn diet now.

I’m getting reports of a sudden surge in hummingbird numbers from a lot of people with feeders. Baby hummingbirds have mostly fledged now—when you’re getting two or three hummers at your feeder with no squabbling at all, that’s invariably a family group composed of a mother and one or two babies. These fledglings bump up the total number of hummingbirds—in a good year, they can close to double it. And adult hummingbirds from Canada are already starting to migrate through, raising our numbers even more. But the dry weather has also had an impact on hummingbirds—as their flowers wilt and natural nectar dries up, more and more of them are seeking out feeders. It’s really important in these conditions to keep your sugar water fresh—change it every 2 or 3 days—and less concentrated than you make it during cold, rainy spells. When hummingbirds can get plenty of water but are cold and need to keep shivering, you can make sugar water as strong as 1/3 of a cup of sugar to one cup of water to keep up their energy. But during droughts, when the little birds don’t have enough water and can get dehydrated, prepare your solutions with a scant ¼ cup of sugar to one cup of water.

All kinds of plants, from birch trees to milkweed, had been wilting before the recent rains. This has an impact on wildlife, from butterflies to birds. We humans notice the increase in flies and decrease in mosquitoes. Birds notice many other changes as well. Since so many warblers depend on caterpillars and other soft-bodied bugs for food, and since so many of them are hard to come by once leaves dry up, they’re getting into their migration mode too. We’re starting to see and hear warblers associating with our backyard chickadees now—if you want to learn their tricky fall plumages, pay close attention to chickadees. Black-capped and Carolina Chickadees have easy-to-recognize calls, are found in just about any habitat with trees from Canada all the way down to Florida and Texas, and their sociable flocks move about, visiting all the best feeding areas, with each chickadee flock intimately familiar with the dangers of their feeding area as well as the best places to find food, water, and resting spots, so warblers instinctively associate with them as they pass through unfamiliar areas. Scanning through each chickadee flock we see or hear in August virtually guarantees us an opportunity to spot some fall warblers.

It’s hard to believe that the month so many people take their summer vacations is the same month when so many birds get into their full autumn migration mode. But even as they hurry south in the nighttime sky, they call to one another to avoid collisions. If you’re outside star gazing, or falling asleep in a tent or with your windows wide open, listen to their little call notes up in the sky. Birds may not be singing nearly as much as in spring, but using our ears we can find them by day with those chickadee flocks, and by night whispering their farewells from high above.